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Sean Ruff

Partner, Financial Services and FinTech at Taft Stettinius & Hollister LLP

Washington, D.C.

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Why they matter

Regulatory lawyer with rare payments-industry-side experience (ex-Square/Block in-house counsel) who structures merchant acquiring, payment facilitation, and money transmitter licensing deals — a go-to diligence resource.

Background

Sean Ruff is a Partner in Taft Stettinius & Hollister's FinTech and Financial Services practice, based in Washington, D.C., which he joined in July 2025. He spent the prior four years as a partner in Cooley's financial services regulatory practice group, and before that co-chaired Morrison & Foerster's fintech practice. Earlier still, he was in-house Director and Lead Payments and Regulatory Counsel at Square, Inc. (now Block, Inc.), giving him rare industry-side plus law-firm-side experience in payments regulation.

Notable deals

  • 2025
    Lateral move to Taft Stettinius & Hollister as partner in the FinTech and Financial Services practices, part of Taft's national fintech build-out
  • 2021
    Joined Cooley LLP as partner in the financial services regulatory practice group, leading money transmitter licensing initiatives for fintech clients
  • 2025
    Ranked in Chambers FinTech Legal: Payments & Lending (Band 3, nationwide), recognized annually since 2020

Call-prep brief

Background

  • Partner, FinTech & Financial Services, Taft Stettinius & Hollister (Washington, D.C.), joined July 2025.
  • Prior: Partner, Financial Services Regulatory practice, Cooley LLP (2021–2025); co-chair, FinTech practice, Morrison & Foerster; in-house Director, Lead Payments & Regulatory Counsel at Square, Inc., now Block, Inc. (2013–2015).
  • J.D., Catholic University of America (2002). Ranked in Chambers FinTech: Payments & Lending (Band 3, 8 consecutive years).

Current focus

  • Regulatory and transactional counsel to fintechs, payment processors, merchant acquirers, and financial institutions.
  • Core areas: money transmitter licensing, BSA/AML compliance, payment facilitation and card program structuring, BNPL and stored-value frameworks, digital assets.

What he cares about

  • Practical, business-first regulatory advice — Chambers describes him as having "worked on both sides—the industry side and the legal side."
  • Helping high-growth payments companies scale compliant licensing infrastructure rather than defaulting to pure risk-aversion.

Recent moves

  • Lateral move from Cooley to Taft (July 2025), joining a fintech bench that also added practice chair Richard Levin and partner Bobby Wenner in 2025.

Potential sensitivities

  • Newly arrived at Taft — likely building his book and will be conflict-cautious re: former Cooley/Square relationships.
  • As outside counsel, bound by privilege — won't discuss specific client matters absent engagement or NDA.

Questions to ask

  1. Which merchant acquirers or payment facilitators has he advised on state money transmitter licensing in the past 18 months, and where were the sticking points?
  2. How are state regulators now distinguishing payment facilitation from merchant acquiring, and what does that mean for licensing-exposure diligence on a target?
  3. Drawing on his Square/Block background, what regulatory red flags do PE buyers most often miss when underwriting a merchant acquiring platform?

Outreach draft

Subject
Quick call on payments regulatory diligence?
Hi Sean, I came across your move to Taft's FinTech practice and your background leading payments regulatory work at Square/Block — exactly the perspective we need right now. We're a PE deal team diligencing a merchant acquiring platform, and we're trying to sharpen our read on state money transmitter licensing exposure and how regulators are currently treating payment facilitation models. Would you have 20-30 minutes in the next week or two for a paid advisory call? Happy to work around your schedule and keep the conversation high-level and conflict-free. Thanks, [Placeholder Name]

Sources